It is sometimes desirable to refrigerate goods that are for sale. For example, beverages such as milk need to be refrigerated in order to extend the milk's shelf-life. Some foods need to be frozen in order to preserve them until they are ready to be cooked. In a commercial setting, refrigerated goods are often stored in refrigerated enclosures that have transparent doors that allow the products within the refrigerated enclosure to be seen without opening the door, thereby increasing product visibility.
Compared to refrigerated enclosures without transparent doors, refrigerated enclosures with transparent doors can be more complicated to operate. For example, the refrigerated enclosures with transparent doors can sometimes have problems with condensation formation on a frame that secures the doors to the refrigerated enclosure. Condensation sometimes forms on the frame due to a temperature difference between a back side of the frame and a front side of the frame. The back side of the frame is generally exposed to the cold, refrigerated space of the refrigerated enclosure and the front side of the frame is generally exposed to warmer ambient air surrounding the refrigerated enclosure.
Condensation formation is sometimes prevented by installing heating elements into the frame to heat the frame to a temperature above a dew point. The dew point is the atmospheric temperature below which water droplets begin to condense from the air. While the use of heating elements is sometimes effective for limiting or preventing condensation, it adds complexity to the refrigerated enclosure system. For example, the use of heating elements requires the use of additional electricity to power the heating elements and decreases safety of the system because electrical components are placed in proximity to people adding or removing goods to the refrigerated enclosure. The use of heating elements also results in the frame itself becoming bulky and heavy. In some refrigerated enclosure designs, the heating elements and other electrical components are integrated into an interior of the frame. Placing the heating elements and other electrical components inside the frame makes servicing the heating elements and other electrical components extremely difficult.